Hybrid architecture incorporating three motor generators and planetary gear sets with two fixed interconnections

ABSTRACT

The electrically variable transmission family of the present invention provides low-content, low-cost electrically variable transmission mechanisms including first, second and third differential gear sets, a battery and three electric machines serving interchangeably as motors or generators. The three motor/generators are operable in a coordinated fashion to yield an EVT with a continuously variable range of speeds (including reverse).

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional PatentApplication No. 60/729,465, filed Oct. 21, 2005, and which is herebyincorporated by reference in its entirety.

TECHNICAL FIELD

The present invention relates to electrically variable transmissionshaving three planetary gear sets and three motor/generators that arecontrollable to provide continuously variable speed ratio ranges.

BACKGROUND OF THE INVENTION

Electric hybrid vehicles offer the potential for significant fueleconomy improvements over their conventional counterparts; however,their overall efficiency is limited by parasitic losses. In single-modeelectric variable transmissions (EVT) these losses are mostly attributedto electric machines rotating at high speeds. Two-mode EVTs offer theadvantage of reduced motor-generator speeds, but often suffer lossesattributed to high-pressure hydraulic pump and clutches needed for modeswitching. Significant vehicle fuel economy gains can be realized if thelosses associated with high-pressure hydraulic pump, clutches and highmotor-generator speeds are substantially eliminated.

SUMMARY OF THE INVENTION

This invention describes continuously-variable mechatronic hybridtransmissions that offer the advantages of multi-mode EVTs without theneed for clutches and the associated high pressure hydraulic pump.

The electrically variable transmission family of the present inventionprovides low-content, low-cost electrically variable transmissionmechanisms including first, second and third differential gear sets, abattery (or similar energy storage device) and three electric machinesserving interchangeably as motors or generators. Preferably, thedifferential gear sets are planetary gear sets, but other geararrangements may be implemented, such as bevel gears or differentialgearing to an offset axis.

In this description, the first, second and third planetary gear sets maybe counted first to third in any order (i.e., left to right, right toleft, etc.).

Each of the three planetary gear sets has three members. The first,second or third member of each planetary gear set can be any one of asun gear, ring gear or carrier, or alternatively a pinion.

Each carrier can be either a single-pinion carrier (simple) or adouble-pinion carrier (compound).

The input shaft is continuously connected with a member of the planetarygear sets. The output shaft is continuously connected with anothermember of the planetary gear sets.

A first interconnecting member continuously connects the first member ofthe first planetary gear set with the first member of the secondplanetary gear.

A second interconnecting member continuously connects the second memberof the second planetary gear set with a first member of the thirdplanetary gear set.

A first motor/generator is connected to a member of the first or secondplanetary gear set.

A second motor/generator is connected to a member of the second or thirdplanetary gear set.

A third motor/generator is connected to a member of the first or thirdplanetary gear set.

In essence, the planetary gear arrangement has seven nodes, five ofwhich are connected with the input shaft, output shaft and threemotor/generators. The electric motor/generators are connected with driveunits, control system and energy storage devices, such as a battery.

The three motor/generators are operated in a coordinated fashion toyield continuously variable forward and reverse speed ratios between theinput shaft and the output shaft, while minimizing the rotational speedsof the motor-generators and optimizing the overall efficiency of thesystem. The tooth ratios of the planetary gear sets can be suitablyselected to match specific applications.

The above features and advantages and other features and advantages ofthe present invention are readily apparent from the following detaileddescription of the best modes for carrying out the invention when takenin connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of a powertrain including anelectrically variable transmission incorporating a family member of thepresent invention;

FIG. 2 is a schematic representation of a powertrain including anelectrically variable transmission incorporating a family member of thepresent invention;

FIG. 3 is a schematic representation of a powertrain including anelectrically variable transmission incorporating a family member of thepresent invention;

FIG. 4 is a schematic representation of a powertrain including anelectrically variable transmission incorporating a family member of thepresent invention;

FIG. 5 is a schematic representation of a powertrain including anelectrically variable transmission incorporating a family member of thepresent invention;

FIG. 6 is a schematic representation of a powertrain including anelectrically variable transmission incorporating a family member of thepresent invention;

FIG. 7 is a schematic representation of a powertrain including anelectrically variable transmission incorporating a family member of thepresent invention;

FIG. 8 is a schematic representation of a powertrain including anelectrically variable transmission incorporating a family member of thepresent invention;

FIG. 9 is a schematic representation of a powertrain including anelectrically variable transmission incorporating a family member of thepresent invention;

FIG. 10 is a schematic representation of a powertrain including anelectrically variable transmission incorporating a family member of thepresent invention; and

FIG. 11 is a schematic representation of a powertrain including anelectrically variable transmission incorporating a family member of thepresent invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIG. 1, a powertrain 10 is shown, including an engine12 connected to one preferred embodiment of the improved electricallyvariable transmission (EVT), designated generally by the numeral 14.Transmission 14 is designed to receive at least a portion of its drivingpower from the engine 12. As shown, the engine 12 has an output shaftthat serves as the input member 17 of the transmission 14. A transienttorque damper (not shown) may also be implemented between the engine 12and the input member 17 of the transmission.

In the embodiment depicted the engine 12 may be a fossil fuel engine,such as a gasoline or diesel engine which is readily adapted to provideits available power output typically delivered at a selectable number ofrevolutions per minute (RPM).

Irrespective of the means by which the engine 12 is connected to thetransmission input member 17, the transmission input member 17 isoperatively connected to a planetary gear set in the transmission 14.

An output member 19 of the transmission 14 is connected to a final drive16.

The transmission 14 utilizes three differential gear sets, preferably inthe nature of planetary gear sets 20, 30 and 40. The planetary gear set20 employs an outer gear member 24, typically designated as the ringgear. The ring gear member 24 circumscribes an inner gear member 22,typically designated as the sun gear. A carrier member 26 rotatablysupports a plurality of planet gears 27 such that each planet gear 27simultaneously, and meshingly engages both the outer, ring gear member24 and the inner, sun gear member 22 of the first planetary gear set 20.

The planetary gear set 30 also employs an outer gear member 34,typically designated as the ring gear. The ring gear member 34circumscribes an inner gear member 32, typically designated as the sungear. A carrier member 36 rotatably supports a plurality of planet gears37 such that each planet gear 37 simultaneously, and meshingly engagesboth the outer, ring gear member 34 and the inner, sun gear member 32 ofthe planetary gear set 30.

The planetary gear set 40 also employs an outer gear member 44,typically designated as the ring gear. The ring gear member 44circumscribes an inner gear member 42, typically designated as the sungear. A carrier member 46 rotatably supports a plurality of planet gears47 such that each planet gear 47 simultaneously, and meshingly engagesboth the outer, ring gear member 44 and the inner, sun gear member 42 ofthe planetary gear set 40.

The input shaft 17 is continuously connected to the sun gear member 32of the planetary gear set 30. The output shaft 19 is continuouslyconnected to the ring gear member 44 of the planetary gear set 40.

A first interconnecting member 70 continuously connects the ring gearmember 24 of the planetary gear set 20 with the carrier member 36 of theplanetary gear set. A second interconnecting member 72 continuouslyconnects the ring gear member 34 of the planetary gear set 30 with thesun gear member 42 of the planetary gear set 40.

The first preferred embodiment 10 also incorporates first, second andthird motor/generators 80, 82 and 84, respectively. The stator of thefirst motor/generator 80 is secured to the transmission housing 60. Therotor of the first motor/generator 80 is secured to the sun gear member22 of the planetary gear set 20.

The stator of the second motor/generator 82 is secured to thetransmission housing 60. The rotor of the second motor/generator 82 issecured to the carrier member 26 of the planetary gear set 20.

The stator of the third motor/generator 84 is secured to thetransmission housing 60. The rotor of the third motor/generator 84 issecured to the carrier member 46 of the planetary gear set 40.

Returning now to the description of the power sources, it should beapparent from the foregoing description, and with particular referenceto FIG. 1, that the transmission 14 selectively receives power from theengine 12. The hybrid transmission also receives power from an electricpower source 86, which is operably connected to a controller 88. Theelectric power source 86 may be one or more batteries. Other electricpower sources, such as capacitors or fuel cells, that have the abilityto provide, or store, and dispense electric power may be used in placeof or in combination with batteries without altering the concepts of thepresent invention. The speed ratio between the input shaft and outputshaft is prescribed by the speeds of the three motor/generators and thering gear/sun gear tooth ratios of the planetary gear sets. Those withordinary skill in the transmission art will recognize that desiredinput/output speed ratios can be realized by suitable selection of thespeeds of the three motor/generators.

Description of a Second Exemplary Embodiment

With reference to FIG. 2, a powertrain 110 is shown, including an engine12 connected to another embodiment of the improved electrically variabletransmission (EVT), designated generally by the numeral 114.Transmission 114 is designed to receive at least a portion of itsdriving power from the engine 12. As shown, the engine 12 has an outputshaft that serves as the input member 17 of the transmission 114. Atransient torque damper (not shown) may also be implemented between theengine 12 and the input member 17 of the transmission.

In the embodiment depicted the engine 12 may be a fossil fuel engine,such as a gasoline or diesel engine which is readily adapted to provideits available power output typically delivered at a selectable number ofrevolutions per minute (RPM).

Irrespective of the means by which the engine 12 is connected to thetransmission input member 17, the transmission input member 17 isoperatively connected to a planetary gear set in the transmission 114.

An output member 19 of the transmission 114 is connected to a finaldrive 16.

The transmission 114 utilizes three differential gear sets, preferablyin the nature of planetary gear sets 120, 130 and 140. The planetarygear set 120 employs an outer gear member 124, typically designated asthe ring gear. The ring gear member 124 circumscribes an inner gearmember 122, typically designated as the sun gear. A carrier member 126rotatably supports a plurality of planet gears 127 such that each planetgear 127 simultaneously, and meshingly engages both the outer, ring gearmember 124 and the inner, sun gear member 122 of the first planetarygear set 120.

The planetary gear set 130 also employs an outer gear member 134,typically designated as the ring gear. The ring gear member 134circumscribes an inner gear member 132, typically designated as the sungear. A carrier member 136 rotatably supports a plurality of planetgears 137 such that each planet gear 137 simultaneously, and meshinglyengages both the outer, ring gear member 134 and the inner, sun gearmember 132 of the planetary gear set 130.

The planetary gear set 140 also employs an outer gear member 144,typically designated as the ring gear. The ring gear member 144circumscribes an inner gear member 142, typically designated as the sungear. A carrier member 146 rotatably supports a plurality of planetgears 147 such that each planet gear 147 simultaneously, and meshinglyengages both the outer, ring gear member 144 and the inner, sun gearmember 142 of the planetary gear set 140.

The input shaft 17 is continuously connected to the sun gear member 142of the planetary gear set 140. The output shaft 19 is continuouslyconnected to the ring gear member 124 of the planetary gear set 120.

A first interconnecting member 170 continuously connects the sun gearmember 122 of the planetary gear set 120 with the carrier member 136 ofthe planetary gear set 130. A second interconnecting member 172continuously connects the carrier member 126 of the planetary gear set120 with the carrier member 146 of the planetary gear set 140.

The second preferred embodiment 110 also incorporates first, second andthird motor/generators 180, 182 and 184, respectively. The stator of thefirst motor/generator 180 is secured to the transmission housing 160.The rotor of the first motor/generator 180 is secured to the ring gearmember 134 of the planetary gear set 130.

The stator of the second motor/generator 182 is secured to thetransmission housing 160. The rotor of the second motor/generator 182 issecured to the sun gear member 132 of the planetary gear set 130.

The stator of the third motor/generator 184 is secured to thetransmission housing 160. The rotor of the third motor/generator 184 issecured to the ring gear member 144 of the planetary gear set 140.

The hybrid transmission 114 receives power from the engine 12, and alsoexchanges power with an electric power source 186, which is operablyconnected to a controller 188.

Description of a Third Exemplary Embodiment

With reference to FIG. 3, a powertrain 210 is shown, including an engine12 connected to another embodiment of the improved electrically variabletransmission (EVT), designated generally by the numeral 214.Transmission 214 is designed to receive at least a portion of itsdriving power from the engine 12. As shown, the engine 12 has an outputshaft that serves as the input member 17 of the transmission 214. Atransient torque damper (not shown) may also be implemented between theengine 12 and the input member 17 of the transmission.

In the embodiment depicted the engine 12 may be a fossil fuel engine,such as a gasoline or diesel engine which is readily adapted to provideits available power output typically delivered at a selectable number ofrevolutions per minute (RPM).

Irrespective of the means by which the engine 12 is connected to thetransmission input member 17, the transmission input member 17 isoperatively connected to a planetary gear set in the transmission 214.

An output member 19 of the transmission 214 is connected to a finaldrive 16.

The transmission 214 utilizes three differential gear sets, preferablyin the nature of planetary gear sets 220, 230 and 240. The planetarygear set 220 employs an outer gear member 224, typically designated asthe ring gear. The ring gear member 224 circumscribes an inner gearmember 222, typically designated as the sun gear. A carrier member 226rotatably supports a plurality of planet gears 227 such that each planetgear 227 simultaneously, and meshingly engages both the outer, ring gearmember 224 and the inner, sun gear member 222 of the first planetarygear set 220.

The planetary gear set 230 also employs an outer gear member 234,typically designated as the ring gear. The ring gear member 234circumscribes an inner gear member 232, typically designated as the sungear. A carrier member 236 rotatably supports a plurality of planetgears 237 such that each planet gear 237 simultaneously, and meshinglyengages both the outer, ring gear member 234 and the inner, sun gearmember 232 of the planetary gear set 230.

The planetary gear set 240 also employs an outer gear member 244,typically designated as the ring gear. The ring gear member 244circumscribes an inner gear member 242, typically designated as the sungear. A carrier member 246 rotatably supports a plurality of planetgears 247 such that each planet gear 247 simultaneously, and meshinglyengages both the outer, ring gear member 244 and the inner, sun gearmember 242 of the planetary gear set 240.

The input shaft 17 is continuously connected to the carrier member 226of the planetary gear set 220. The output shaft 19 is continuouslyconnected to the carrier member 236 of the planetary gear set 230.

A first interconnecting member 270 continuously connects the ring gearmember 224 with the sun gear member 232. A second interconnecting member272 continuously connects the ring gear member 234 with the carriermember 246.

The preferred embodiment 210 also incorporates first, second and thirdmotor/generators 280, 282 and 284, respectively. The stator of the firstmotor/generator 280 is secured to the transmission housing 260. Therotor of the first motor/generator 280 is secured to the sun gear member222 of the planetary gear set 240.

The stator of the second motor/generator 282 is secured to thetransmission housing 260. The rotor of the second motor/generator 282 issecured to the ring gear member 244 of the planetary gear set 240.

The stator of the third motor/generator 284 is secured to thetransmission housing 260. The rotor of the third motor/generator 284 issecured to the sun gear member 242 of the planetary gear set 240.

The hybrid transmission 214 receives power from the engine 12, and alsoexchanges power with an electric power source 286, which is operablyconnected to a controller 288.

Description of a Fourth Exemplary Embodiment

With reference to FIG. 4, a powertrain 310 is shown, including an engine12 connected to another embodiment of the improved electrically variabletransmission (EVT), designated generally by the numeral 314.Transmission 314 is designed to receive at least a portion of itsdriving power from the engine 12. As shown, the engine 12 has an outputshaft that serves as the input member 17 of the transmission 314. Atransient torque damper (not shown) may also be implemented between theengine 12 and the input member 17 of the transmission.

In the embodiment depicted the engine 12 may be a fossil fuel engine,such as a gasoline or diesel engine which is readily adapted to provideits available power output typically delivered at a selectable number ofrevolutions per minute (RPM).

Irrespective of the means by which the engine 12 is connected to thetransmission input member 17, the transmission input member 17 isoperatively connected to a planetary gear set in the transmission 14. Anoutput member 19 of the transmission 314 is connected to a final drive16.

The transmission 314 utilizes three differential gear sets, preferablyin the nature of planetary gear sets 320, 330 and 340. The planetarygear set 320 employs an outer gear member 324, typically designated asthe ring gear. The ring gear member 324 circumscribes an inner gearmember 322, typically designated as the sun gear. A carrier member 326rotatably supports a plurality of planet gears 327 such that each planetgear 327 simultaneously, and meshingly engages both the outer, ring gearmember 324 and the inner, sun gear member 322 of the first planetarygear set 320.

The planetary gear set 330 also employs an outer gear member 334,typically designated as the ring gear. The ring gear member 334circumscribes an inner gear member 332, typically designated as the sungear. A carrier member 336 rotatably supports a plurality of planetgears 337 such that each planet gear 337 simultaneously, and meshinglyengages both the outer, ring gear member 334 and the inner, sun gearmember 332 of the planetary gear set 330.

The planetary gear set 340 also employs an outer gear member 344,typically designated as the ring gear. The ring gear member 344circumscribes an inner gear member 342, typically designated as the sungear. A carrier member 346 rotatably supports a plurality of planetgears 347 such that each planet gear 347 simultaneously, and meshinglyengages both the outer, ring gear member 344 and the inner, sun gearmember 342 of the planetary gear set 340.

The input shaft 17 is continuously connected to the ring gear member 324of the planetary gear set 320. The output shaft 19 is continuouslyconnected to the ring gear member 344 of the planetary gear set 340.

A first interconnecting member 370 continuously connects the carriermember 326 with the sun gear member 342. A second interconnecting member372 continuously connects the carrier member 336 with the carrier member346.

The preferred embodiment 310 also incorporates first, second and thirdmotor/generators 380, 382 and 384, respectively. The stator of the firstmotor/generator 380 is secured to the transmission housing 360. Therotor of the first motor/generator 380 is secured to the sun gear member322.

The stator of the second motor/generator 382 is secured to thetransmission housing 360. The rotor of the second motor/generator 382 issecured to the ring gear member 334.

The stator of the third motor/generator 384 is secured to thetransmission housing 360. The rotor of the third motor/generator 384 issecured to the sun gear member 332.

The hybrid transmission 314 receives power from the engine 12, and alsoexchanges power with an electric power source 386, which is operablyconnected to a controller 388.

Description of a Fifth Exemplary Embodiment

With reference to FIG. 5, a powertrain 410 is shown, including an engine12 connected to another embodiment of the improved electrically variabletransmission (EVT), designated generally by the numeral 414.Transmission 414 is designed to receive at least a portion of itsdriving power from the engine 12. As shown, the engine 12 has an outputshaft that serves as the input member 17 of the transmission 414. Atransient torque damper (not shown) may also be implemented between theengine 12 and the input member 17 of the transmission.

In the embodiment depicted the engine 12 may be a fossil fuel engine,such as a gasoline or diesel engine which is readily adapted to provideits available power output typically delivered at a selectable number ofrevolutions per minute (RPM).

Irrespective of the means by which the engine 12 is connected to thetransmission input member 17, the transmission input member 17 isoperatively connected to a planetary gear set in the transmission 414.An output member 19 of the transmission 414 is connected to a finaldrive 16.

The transmission 414 utilizes three differential gear sets, preferablyin the nature of planetary gear sets 420, 430 and 440. The planetarygear set 420 employs an outer gear member 424, typically designated asthe ring gear. The ring gear member 424 circumscribes an inner gearmember 422, typically designated as the sun gear. A carrier member 426rotatably supports a plurality of planet gears 427 such that each planetgear 427 simultaneously, and meshingly engages both the outer, ring gearmember 424 and the inner, sun gear member 422 of the first planetarygear set 420.

The planetary gear set 430 also employs an outer gear member 434,typically designated as the ring gear. The ring gear member 434circumscribes an inner gear member 432, typically designated as the sungear. A carrier member 436 rotatably supports a plurality of planetgears 437 such that each planet gear 437 simultaneously, and meshinglyengages both the outer, ring gear member 434 and the inner, sun gearmember 432 of the planetary gear set 430.

The planetary gear set 440 also employs an outer gear member 444,typically designated as the ring gear. The ring gear member 444circumscribes an inner gear member 442, typically designated as the sungear. A carrier member 446 rotatably supports a plurality of planetgears 447 such that each planet gear 447 simultaneously, and meshinglyengages both the outer, ring gear member 444 and the inner, sun gearmember 442 of the planetary gear set 440.

The input shaft 17 is continuously connected to the ring gear member424. The output shaft 19 is continuously connected to the carrier member446.

A first interconnecting member 470 continuously connects the carriermember 426 with the carrier member 436. A second interconnecting member472 continuously connects the sun gear member 432 with the ring gearmember 444.

The preferred embodiment 410 also incorporates first, second and thirdmotor/generators 480, 482 and 484, respectively. The stator of the firstmotor/generator 480 is secured to the transmission housing 460. Therotor of the first motor/generator 480 is secured to the sun gear member422.

The stator of the second motor/generator 482 is secured to thetransmission housing 460. The rotor of the second motor/generator 482 issecured to the ring gear member 434.

The stator of the third motor/generator 484 is secured to thetransmission housing 460. The rotor of the third motor/generator 484 issecured to the sun gear member 442.

The hybrid transmission 414 receives power from the engine 12, and alsoexchanges power with an electric power source 486, which is operablyconnected to a controller 488.

Description of a Sixth Exemplary Embodiment

With reference to FIG. 6, a powertrain 510 is shown, including an engine12 connected to another embodiment of the improved electrically variabletransmission (EVT), designated generally by the numeral 514.Transmission 514 is designed to receive at least a portion of itsdriving power from the engine 12. As shown, the engine 12 has an outputshaft that serves as the input member 17 of the transmission 514. Atransient torque damper (not shown) may also be implemented between theengine 12 and the input member 17 of the transmission.

In the embodiment depicted the engine 12 may be a fossil fuel engine,such as a gasoline or diesel engine which is readily adapted to provideits available power output typically delivered at a selectable number ofrevolutions per minute (RPM).

Irrespective of the means by which the engine 12 is connected to thetransmission input member 17, the transmission input member 17 isoperatively connected to a planetary gear set in the transmission 514.An output member 19 of the transmission 514 is connected to a finaldrive 16.

The transmission 514 utilizes three differential gear sets, preferablyin the nature of planetary gear sets 520, 530 and 540. The planetarygear set 520 employs an outer gear member 524, typically designated asthe ring gear. The ring gear member 524 circumscribes an inner gearmember 522, typically designated as the sun gear. A carrier member 526rotatably supports a plurality of planet gears 527 such that each planetgear 527 simultaneously, and meshingly engages both the outer, ring gearmember 524 and the inner, sun gear member 522 of the planetary gear set520.

The planetary gear set 530 also employs an outer gear member 534,typically designated as the ring gear. The ring gear member 534circumscribes an inner gear member 532, typically designated as the sungear. A carrier member 536 rotatably supports a plurality of planetgears 537 such that each planet gear 537 simultaneously, and meshinglyengages both the outer, ring gear member 534 and the inner, sun gearmember 532 of the planetary gear set 530.

The planetary gear set 540 also employs an outer gear member 544,typically designated as the ring gear. The ring gear member 544circumscribes an inner gear member 542, typically designated as the sungear. A carrier member 546 rotatably supports a plurality of planetgears 547 such that each planet gear 547 simultaneously, and meshinglyengages both the outer, ring gear member 544 and the inner, sun gearmember 542 of the planetary gear set 540.

The input shaft 17 is continuously connected to the carrier member 526.The output shaft 19 is continuously connected to the ring gear member544.

A first interconnecting member 570 continuously connects the ring gearmember 524 with the carrier member 536. A second interconnecting member572 continuously connects the sun gear member 532 with the carriermember 546.

The preferred embodiment 510 also incorporates first, second and thirdmotor/generators 580, 582 and 584, respectively. The stator of the firstmotor/generator 580 is secured to the transmission housing 560. Therotor of the first motor/generator 580 is secured to the sun gear member522.

The stator of the second motor/generator 582 is secured to thetransmission housing 560. The rotor of the second motor/generator 582 issecured to the ring gear member 534.

The stator of the third motor/generator 584 is secured to thetransmission housing 560. The rotor of the third motor/generator 584 issecured to the sun gear member 542.

The hybrid transmission 514 receives power from the engine 12, and alsoexchanges power with an electric power source 586, which is operablyconnected to a controller 588.

Description of a Seventh Exemplary Embodiment

With reference to FIG. 7, a powertrain 610 is shown, including an engine12 connected to another embodiment of the improved electrically variabletransmission (EVT), designated generally by the numeral 614.Transmission 614 is designed to receive at least a portion of itsdriving power from the engine 12. As shown, the engine 12 has an outputshaft that serves as the input member 17 of the transmission 614. Atransient torque damper (not shown) may also be implemented between theengine 12 and the input member 17 of the transmission.

In the embodiment depicted the engine 12 may be a fossil fuel engine,such as a gasoline or diesel engine which is readily adapted to provideits available power output typically delivered at a selectable number ofrevolutions per minute (RPM).

Irrespective of the means by which the engine 12 is connected to thetransmission input member 17, the transmission input member 17 isoperatively connected to a planetary gear set in the transmission 614.An output member 19 of the transmission 614 is connected to a finaldrive 16.

The transmission 614 utilizes three differential gear sets, preferablyin the nature of planetary gear sets 620, 630 and 640. The planetarygear set 620 employs an outer gear member 624, typically designated asthe ring gear. The ring gear member 624 circumscribes an inner gearmember 622, typically designated as the sun gear. A carrier member 626rotatably supports a plurality of planet gears 627 such that each planetgear 627 simultaneously, and meshingly engages both the outer, ring gearmember 624 and the inner, sun gear member 622 of the first planetarygear set 620.

The planetary gear set 630 also employs an outer gear member 634,typically designated as the ring gear. The ring gear member 634circumscribes an inner gear member 632, typically designated as the sungear. A carrier member 636 rotatably supports a plurality of planetgears 637 such that each planet gear 637 simultaneously, and meshinglyengages both the outer, ring gear member 634 and the inner, sun gearmember 632 of the planetary gear set 630.

The planetary gear set 640 also employs an outer gear member 644,typically designated as the ring gear. The ring gear member 644circumscribes an inner gear member 642, typically designated as the sungear. A carrier member 646 rotatably supports a plurality of planetgears 647 such that each planet gear 647 simultaneously, and meshinglyengages both the outer, ring gear member 644 and the inner, sun gearmember 642 of the planetary gear set 640.

The input shaft 17 is continuously connected to the sun gear member 622.The output shaft 19 is continuously connected to the ring gear member644.

A first interconnecting member 670 continuously connects the carriermember 626 with the ring gear member 634. A second interconnectingmember 672 continuously connects the sun gear member 632 with the sungear member 642.

The preferred embodiment 610 also incorporates first, second and thirdmotor/generators 680, 682 and 684, respectively. The stator of the firstmotor/generator 680 is secured to the transmission housing 660. Therotor of the first motor/generator 680 is secured to the ring gearmember 624.

The stator of the second motor/generator 682 is secured to thetransmission housing 660. The rotor of the second motor/generator 682 issecured to the carrier member 636.

The stator of the third motor/generator 684 is secured to thetransmission housing 660. The rotor of the third motor/generator 684 issecured to the carrier member 646.

The hybrid transmission 614 receives power from the engine 12, and alsoexchanges power with an electric power source 686, which is operablyconnected to a controller 688.

Description of an Eighth Exemplary Embodiment

With reference to FIG. 8, a powertrain 710 is shown, including an engine12 connected to another embodiment of the improved electrically variabletransmission (EVT), designated generally by the numeral 714.Transmission 714 is designed to receive at least a portion of itsdriving power from the engine 12. As shown, the engine 12 has an outputshaft that serves as the input member 17 of the transmission 714. Atransient torque damper (not shown) may also be implemented between theengine 12 and the input member 17 of the transmission.

In the embodiment depicted the engine 12 may be a fossil fuel engine,such as a gasoline or diesel engine which is readily adapted to provideits available power output typically delivered at a selectable number ofrevolutions per minute (RPM).

Irrespective of the means by which the engine 12 is connected to thetransmission input member 17, the transmission input member 17 isoperatively connected to a planetary gear set in the transmission 714.An output member 19 of the transmission 714 is connected to a finaldrive 16.

The transmission 714 utilizes three differential gear sets, preferablyin the nature of planetary gear sets 720, 730 and 740. The planetarygear set 720 employs an outer gear member 724, typically designated asthe ring gear. The ring gear member 724 circumscribes an inner gearmember 722, typically designated as the sun gear. A carrier member 726rotatably supports a plurality of planet gears 727 such the each planetgear 727 simultaneously, and meshingly engages both the outer, ring gearmember 724 and the inner, sun gear member 722 of the planetary gear set720.

The planetary gear set 730 also employs an outer gear member 734,typically designated as the ring gear. The ring gear member 734circumscribes an inner gear member 732, typically designated as the sungear. A carrier member 736 rotatably supports a plurality of planetgears 737, 738. Each planet gear 737 meshingly engages the sun gearmember 732 and each planet gear 738 simultaneously, and meshinglyengages both the ring gear member 734 and the respective planet gear737.

The planetary gear set 740 also employs an outer gear member 744,typically designated as the ring gear. The ring gear member 744circumscribes an inner gear member 742, typically designated as the sungear. A carrier member 746 rotatably supports a plurality of planetgears 747 such that each planet gear 747 simultaneously, and meshinglyengages both the outer, ring gear member 744 and the inner, sun gearmember 742 of the planetary gear set 740.

The input shaft 17 is continuously connected to the ring gear member724. The output shaft 19 is continuously connected to the ring gearmember 744.

A first interconnecting member 770 continuously connects the sun gearmember 722 with the carrier member 736. A second interconnecting member772 continuously connects the sun gear member 732 with the carriermember 746.

The preferred embodiment 710 also incorporates first, second and thirdmotor/generators 780, 782 and 784, respectively. The stator of the firstmotor/generator 780 is secured to the transmission housing 760. Therotor of the first motor/generator 780 is secured to the carrier member726.

The stator of the second motor/generator 782 is secured to thetransmission housing 760. The rotor of the second motor/generator 782 issecured to the ring gear member 734.

The stator of the third motor/generator 784 is secured to thetransmission housing 760. The rotor of the third motor/generator 784 issecured to the sun gear member 742.

The hybrid transmission 714 receives power from the engine 12, and alsoexchanges power with an electric power source 786, which is operablyconnected to a controller 788.

Description of a Ninth Exemplary Embodiment

With reference to FIG. 9, a powertrain 810 is shown, including an engine12 connected to another embodiment of the improved electrically variabletransmission (EVT), designated generally by the numeral 814.Transmission 814 is designed to receive at least a portion of itsdriving power from the engine 12. As shown, the engine 12 has an outputshaft that serves as the input member 17 of the transmission 814. Atransient torque damper (not shown) may also be implemented between theengine 12 and the input member 17 of the transmission.

In the embodiment depicted the engine 12 may be a fossil fuel engine,such as a gasoline or diesel engine which is readily adapted to provideits available power output typically delivered at a selectable number ofrevolutions per minute (RPM).

Irrespective of the means by which the engine 12 is connected to thetransmission input member 17, the transmission input member 17 isoperatively connected to a planetary gear set in the transmission 814.An output member 19 of the transmission 814 is connected to a finaldrive 16.

The transmission 814 utilizes three differential gear sets, preferablyin the nature of planetary gear sets 820, 830 and 840. The planetarygear set 820 employs an outer gear member 824, typically designated asthe ring gear. The ring gear member 824 circumscribes an inner gearmember 822, typically designated as the sun gear. A carrier member 826rotatably supports a plurality of planet gears 827 such that each planetgear 827 simultaneously, and meshingly engages both the outer, ring gearmember 824 and the inner, sun gear member 822 of the planetary gear set820.

The planetary gear set 830 also employs an outer gear member 834,typically designated as the ring gear. The ring gear member 834circumscribes an inner gear member 832, typically designated as the sungear. A carrier member 836 rotatably supports a plurality of planetgears 837 such that each planet gear 837 simultaneously, and meshinglyengages both the outer, ring gear member 834 and the inner, sun gearmember 832 of the planetary gear set 830.

The planetary gear set 840 also employs an outer gear member 844,typically designated as the ring gear. The ring gear member 844circumscribes an inner gear member 842, typically designated as the sungear. A carrier member 846 rotatably supports a plurality of planetgears 847 such that each planet gear 847 simultaneously, and meshinglyengages both the outer, ring gear member 844 and the inner, sun gearmember 842 of the planetary gear set 840.

The input shaft 17 is continuously connected to the carrier member 826.The output shaft 19 is continuously connected to the carrier member 846.

A first interconnecting member 870 continuously connects the ring gearmember 824 with the carrier member 836. A second interconnecting member872 continuously connects the sun gear member 832 with the sun gearmember 842.

The preferred embodiment 810 also incorporates first, second and thirdmotor/generators 880, 882 and 884, respectively. The stator of the firstmotor/generator 880 is secured to the transmission housing 860. Therotor of the first motor/generator 880 is secured to the sun gear member822.

The stator of the second motor/generator 882 is secured to thetransmission housing 860. The rotor of the second motor/generator 882 issecured to the ring gear member 834.

The stator of the third motor/generator 884 is secured to thetransmission housing 860. The rotor of the third motor/generator 884 issecured to the ring gear member 844.

The hybrid transmission 814 receives power from the engine 12, and alsoexchanges power with an electric power source 886, which is operablyconnected to a controller 888.

Description of a Tenth Exemplary Embodiment

With reference to FIG. 10, a powertrain 910 is shown, including anengine 12 connected to another embodiment of the improved electricallyvariable transmission (EVT), designated generally by the numeral 914.Transmission 914 is designed to receive at least a portion of itsdriving power from the engine 12. As shown, the engine 12 has an outputshaft that serves as the input member 17 of the transmission 914. Atransient torque damper (not shown) may also be implemented between theengine 12 and the input member 17 of the transmission.

In the embodiment depicted the engine 12 may be a fossil fuel engine,such as a gasoline or diesel engine which is readily adapted to provideits available power output typically delivered at a selectable number ofrevolutions per minute (RPM).

Irrespective of the means by which the engine 12 is connected to thetransmission input member 17, the transmission input member 17 isoperatively connected to a planetary gear set in the transmission 914.An output member 19 of the transmission 914 is connected to a finaldrive 16.

The transmission 914 utilizes three differential gear sets, preferablyin the nature of planetary gear sets 920, 930 and 940. The planetarygear set 920 employs an outer gear member 924, typically designated asthe ring gear. The ring gear member 924 circumscribes an inner gearmember 922, typically designated as the sun gear. A carrier member 926rotatably supports a plurality of planet gears 927 such that each planetgear 927 simultaneously, and meshingly engages both the outer, ring gearmember 924 and the inner, sun gear member 922 of the planetary gear set920.

The planetary gear set 930 employs an outer gear member 934, typicallydesignated as the ring gear. The ring gear member 934 circumscribes aninner gear member 932, typically designated as the sun gear. A carriermember 936 rotatably supports a plurality of planet gears 937 such thateach planet gear 937 simultaneously, and meshingly engages both theouter, ring gear member 934 and the inner, sun gear member 932 of theplanetary gear set 930.

The planetary gear set 940 employs an outer gear member 944, typicallydesignated as the ring gear. The ring gear member 944 circumscribes aninner gear member 942, typically designated as the sun gear. A carriermember 946 rotatably supports a plurality of planet gears 947 such thateach planet gear 947 simultaneously, and meshingly engages both theouter, ring gear member 944 and the inner, sun gear member 942 of theplanetary gear set 940.

The input shaft 17 is continuously connected to the carrier member 936.The output shaft 19 is continuously connected to the ring gear member944.

A first interconnecting member 970 continuously connects the carriermember 926 with the ring gear member 934. A second interconnectingmember 972 continuously connects the sun gear member 932 with the sungear member 942.

The preferred embodiment 910 also incorporates first, second and thirdmotor/generators 980, 982 and 984, respectively. The stator of the firstmotor/generator 980 is secured to the transmission housing 960. Therotor of the first motor/generator 980 is secured to the sun gear member922.

The stator of the second motor/generator 982 is secured to thetransmission housing 960. The rotor of the second motor/generator 982 issecured to the ring gear member 924.

The stator of the third motor/generator 984 is secured to thetransmission housing 960. The rotor of the third motor/generator 984 issecured to the carrier member 946.

The hybrid transmission 914 receives power from the engine 12, and alsoexchanges power with an electric power source 986, which is operablyconnected to a controller 988.

Description of an Eleventh Exemplary Embodiment

With reference to FIG. 11, a powertrain 1010 is shown, including anengine 12 connected to another embodiment of the improved electricallyvariable transmission (EVT), designated generally by the numeral 1014.Transmission 1014 is designed to receive at least a portion of itsdriving power from the engine 12. As shown, the engine 12 has an outputshaft that serves as the input member 17 of the transmission 1014. Atransient torque damper (not shown) may also be implemented between theengine 12 and the input member 17 of the transmission.

In the embodiment depicted the engine 12 may be a fossil fuel engine,such as a gasoline or diesel engine which is readily adapted to provideits available power output typically delivered at a selectable number ofrevolutions per minute (RPM).

Irrespective of the means by which the engine 12 is connected to thetransmission input member 17, the transmission input member 17 isoperatively connected to a planetary gear set in the transmission 1014.An output member 19 of the transmission 1014 is connected to a finaldrive 16.

The transmission 1014 utilizes three differential gear sets, preferablyin the nature of planetary gear sets 1020, 1030 and 1040. The planetarygear set 1020 employs an outer gear member 1024, typically designated asthe ring gear. The ring gear member 1024 circumscribes an inner gearmember 1022, typically designated as the sun gear. A carrier member 1026rotatably supports a plurality of planet gears 1027 such that eachplanet gear 1027 simultaneously, and meshingly engages both the outer,ring gear member 1024 and the inner, sun gear member 1022 of theplanetary gear set 1020.

The planetary gear set 1030 also employs an outer gear member 1034,typically designated as the ring gear. The ring gear member 1034circumscribes an inner gear member 1032, typically designated as the sungear. A carrier member 1036 rotatably supports a plurality of planetgears 1037 such that each planet gear 1037 simultaneously, and meshinglyengages both the outer, ring gear member 1034 and the inner, sun gearmember 1032 of the planetary gear set 1030.

The planetary gear set 1040 also employs an outer gear member 1044,typically designated as the ring gear. The ring gear member 1044circumscribes an inner gear member 1042, typically designated as the sungear. A carrier member 1046 rotatably supports a plurality of planetgears 1047 such that each planet gear 1047 simultaneously, and meshinglyengages both the outer, ring gear member 1044 and the inner, sun gearmember 1042 of the planetary gear set 1040.

The input shaft 17 is continuously connected to the carrier member 1026.The output shaft 19 is continuously connected to the carrier member1046.

A first interconnecting member 1070 continuously connects the ring gearmember 1024 with the carrier member 1036. A second interconnectingmember 1072 continuously connects the ring gear member 1034 with the sungear member 1042.

The preferred embodiment 1010 also incorporates first, second and thirdmotor/generators 1080, 1082 and 1084, respectively. The stator of thefirst motor/generator 1080 is secured to the transmission housing 1060.The rotor of the first motor/generator 1080 is secured to the sun gearmember 1022 via an offset drive 1090, such as a belt or chain, which maychange the speed ratio.

The stator of the second motor/generator 1082 is secured to thetransmission housing 1060. The rotor of the second motor/generator 1082is secured to the sun gear member 1032.

The stator of the third motor/generator 1084 is secured to thetransmission housing 1060. The rotor of the third motor/generator 1084is secured to the ring gear member 1044 via offset gear 1092, which maychange the speed ratio.

The hybrid transmission 1014 receives power from the engine 12, and alsoexchanges power with an electric power source 1086, which is operablyconnected to a controller 1088.

While the best modes for carrying out the invention have been describedin detail, those familiar with the art to which this invention relateswill recognize various alternative designs and embodiments forpracticing the invention within the scope of the appended claims.

1. An electrically variable transmission comprising: an input member toreceive power from an engine; an output member; first, second and thirdmotor/generators; first, second and third differential gear sets eachhaving first, second and third members; said input member beingcontinuously connected with one of said first, second and third membersof said gear sets, and said output member being continuously connectedwith another one of said first, second and third members of said gearsets; a first interconnecting member continuously connecting said firstmember of said first gear set with said first member of said second gearset; a second interconnecting member continuously connecting said secondmember of said second gear set with said first member of said third gearset; said first motor/generator being continuously connected with one ofsaid first, second and third members of said first or second gear set;said second motor/generator being continuously connected with one ofsaid first, second and third members of said second or third gear set;said third motor/generator being continuously connected with one of saidfirst, second and third members of said first or third gear set; whereinsaid first, second and third motor/generators are operable to provide anelectrically variable transmission with a continuously variable range ofspeed ratios between said input member and said output member.
 2. Theelectrically variable transmission of claim 1, wherein said first,second and third differential gear sets are planetary gear sets.
 3. Theelectrically variable transmission of claim 2, wherein carriers of eachof said planetary gear sets are single-pinion carriers.
 4. Theelectrically variable transmission of claim 2, wherein at least onecarrier of said planetary gear sets is a double-pinion carrier.
 5. Theelectrically variable transmission of claim 1, wherein at least one ofsaid motor/generators is connected with said gear sets through a fixedor variable speed ratio device, wherein said fixed or variable speedratio device is a conventional gear set, belt drive, chain drive orcombinations thereof.
 6. The electrically variable transmission of claim1, wherein the electrically variable transmission is characterized bythe absence of clutches.
 7. An electrically variable transmissioncomprising: an input member to receive power from an engine; an outputmember; first, second and third motor/generators; first, second andthird differential gear sets each having first, second and thirdmembers; said input member being continuously connected with one of saidfirst, second and third members of said gear sets, and said outputmember being continuously connected with another one of said first,second and third members of said gear sets; a first interconnectingmember continuously connecting said first member of said first gear setwith said first member of said second gear set; a second interconnectingmember continuously connecting said second member of said second gearset with said first member of said third gear set; said first, secondand third motor/generators being continuously connected with said first,second and third members of said gear sets; wherein said first, secondand third motor/generators are operable to provide an electricallyvariable transmission with a continuously variable range of speed ratiosbetween said input member and said output member.
 8. The electricallyvariable transmission of claim 7, wherein said first, second and thirddifferential gear sets are planetary gear sets.
 9. The electricallyvariable transmission of claim 8, wherein carriers of each of saidplanetary gear sets are single-pinion carriers.
 10. The electricallyvariable transmission of claim 8, wherein at least one carrier of saidplanetary gear sets is a double-pinion carrier.
 11. The electricallyvariable transmission of claim 7, wherein at least one of saidmotor/generators is connected with said gear sets through a fixed orvariable speed ratio device, wherein said fixed or variable speed ratiodevice is a conventional gear set, belt drive, chain drive orcombinations thereof.